Landslides distribution at tributaries with different evolution stages in Jiangjia Gully, southwestern China

Abstract. Landslide susceptibility assessment is of great significance for the disaster prediction and prevention. At present, most studies used statistical methods by the influence factors of landslide distribution, or based on physical models to determine the assessment result, the research of these methods was mainly focused on the gully scale. At the same time, these methods did not focus on the specific principle of material storage. In this paper, the surface erosion index, being the integral of the hypsometric curve, is adopted to explore the landslides distribution characteristic in different tributaries of the gully. Firstly, 81 tributaries of JJG are taken from DEM with 10 m grid cells, and the hypsometric curves are used to characterize their evolution stages; five stages are identified by the evolution index (EI, the integral of the hypsometric curves) and most tributaries are in relative youth stage with EI between 0.5 and 0.6. Then 906 landslides are interpreted from Quickbird satellite image of 0.61 m resolution. It is found that LD (LD = landslides number in a tributary/ the tributary area) increases exponentially with EI, while LA_p (LA_p = landslides area in a tributary/the tributary area) fluctuates with EI, meaning that landslides are inclined to occur in tributaries with EI between 0.5 and 0.6, and thus these tributaries are the main material sources supplying for debris flows.